Spark ignition mechanism for domestic oil burners



De. 6, 1932. ALDRICH 1,889,968

SPARK ISNITION MECHANISM FOR DOMESTIC CIL BURNERS Fild May l. 1925 3 Sheets-Sheet 1 1 l. ALDRICH 1,889,968

SPARK IGNITION MECHANISM FOR DOMESTIC OIL BURNERS Dec. 6, 1932.

Filed May l, 1925 3 Sheets-Sheet 2 wwN Dec. 6, 1932.' l l, ALDR|H 1,889,968

SYARK IGNITION MECHANISM FOR DOMESTIC OIL BURNERS Filed May l, 1925 I5 Sheets-Sheet 5 Patented Dee. e, 1932 UNITED STATES PATENT OFFICE y LOYD I. vALDRICII, F PEORIA, ILLINOIS, ASSIGNOR T0 PREFERRED OIL BUB/NEBIS, INC.,

. OF PEORIA, ILLINOIS, A CORPORATION OF ILLINOIS SPARK IQNITIQN MECHANISM FOR DOMESTIC OIL BURNEES area for but"a limited time'after the commencement of operation of the burner.

Another object of the invention is in the provision of asparkignition device for oil burners, whereby the. commencement of operation of said burner will operate to project thespa'rking member into kthe zoneof com-l bustion, and mechanism for withdrawing said sparking members after a sufficient period for ignition.

Still another object of the invention is in` the provision of spark ignition mechanism for domestic oil burners, whereby the sparking member will be projected into the combustion area upon commencement of operation of the burner and not withdrawn until ignition of the projected fuel .mixture has resulted. f c

A further object of the invention is in the provision of mechanism controlled by the operation of a domestic oil burner for pro# jecting a sparking mechanism into the zone of combustion and for withdrawing same thereafter. f

Still another object of the invention is in the provision of mechanism controlled by the initial operation of a domestic oil .burner for projecting a sparking device into the zone of combustion, and mechanism directly responsive to combustion conditions adapted to withdraw said spark member from the combustion area.

Yet another object of the' invention is in the provision of a sparking device for do'- vmestic oil burners, said sparking device comprising pressure operated means for projecting same into the zone of combustion upon the commencement of operation of the burner, and means for withdrawing same after ignition of the projected Lfuel mixture has been insured.

In the drawings 50r Fig. 1 isa diagrammatic view of the elec- Application led May ,1925. Serial No. 27,182.

trical connections, including a perspective,' partially in section, of the burner;

Fig. 2 is an enlarged diagrammatic showing, partially in section, disclosing the prinv ciple 'of operation of the burner; 55

Fig. 3 is an enlarged detail ofmthe latch on the safety switch;

Fig. 4 is a planview from above, of the' spark ignition mechanism;

Fig. 5 is a side elevation of same, with portions broken away `for a clearer disclosure; b Fig. 6 is an enlarged detail of the pressure operated mechanism controlling the action of the spark ignition members, and

Fig. 7 is a detail showing of the manner of mounting the electrodes in the spark ignition mechanism.

Referring to the drawings, I have shown in Fig. 1 a general view of the domestic oil burner, as Well as complete diagrammatical showing` of the electrical control and safety mechanism therefor. The o1l burner, per

se, has been described in detail in my copending application, Serial No. 721,724, filed June 23, 1924, and in view of the fact that my present mechanism would beI adaptable, with minor changes, to any of the Well known types of domestic oil burners, only a general description of the oil burner will be given.

vThe mechanical portions of the burner comprise an electric motor 10, having conneet-ion withthe atomizing portions, including a common shaft 11, driven by the electric motor, which shaft is mounted in suitable bearings. A sirocco type of fan, 12, is driven by said ymain shaft, said fan being located adjacentthe connection of the drive shaft with the motor. Immediately adjacent the sirocco fan and attached thereto by suitable brackets is a liquid pressure air pump 13, said pump also being driven bythe common drive shaft 11. An oil pump 14 is located at the eXtremity of the common drive shaft, and is also driven thereby. From the oil pump an oil line 15 leads to a venturi 16, said venturi also having connection 17 with the liquid'pressure air pump. Disposed adjacent the venturi and in the oil line is a needle valve or fuel control member 18. Also adjacent the fuel pump is a pressure valve 19 and a fuel by-pass 20 to a fuel containeror reservoir (not shown). A common fuel mixture tube 21 is carried from the venturi to the nozzle 22 disposed within or substantially Within the combustion chamber of the furnace. The fuel discharge tube passes through the blast housing 23 from the fan member. A- sump 24- is located inl the fuel mixture discharge tube in such manner as to trap any unatomized fuel, the same being returned through the lead 25 to the liquid pressure airv pump, the same providing means for replenishing the pump. Angularly disposed vane members26 are mounted in' the end` of the blast housing adjacent the combustion chamber, and immediately surrounding the nozzle 22, the same acting to deflect the blast from the fan in an opposite and angular direction to the cone of the discharging fuel mixture. l An air inlet to the liquid fuel air pressure pump is provided in a downwardly disposed member 27, the same projecting into the sump. or base of the burner. A diaphragm member 28 is connected tothe air pressure pump and is operated thereby in such manner as to control the flow of fuel to the burner,the

same being accomplishedl by means of a formal valve member 29 in the fuel line .controlled by a lever 29a connected to and operated by the diaphragm.

Before describing the electrical circuitand connections controlling theoperation of the burner, it is thought best to first describe the physical portions which make up the safety mechanism for the-burner, as well as the ignition mechanism, in view of the fact that said electrical-'circuit includesl and co-oprates with said members.\

Includedl in the safety mechanism is a commonly called stack thermostat, the same de` riving its name from the fact that it is loof simplicity of assembly,

vthermostat might ,well be located any; place cated .in thestack of the furnace, although this location has been used merely "because and. the safety where it would be. sensitive to v j combustion conditions within the furnace,

This stack thermostat generally includes elements sensitive` to temperature condltlons, as well asa mer' cury contact bulb B controlled by the movement of the thermostat. This mercury bulb contains therein'contact points later to be described in the electrical circuit of the' burner. Apipe from the air pressure pump leads to a solenoid valve member 30 that is controlled by a coil 31 included in the electricalbcircuit .of the burner, and llater to be described.

From the valve, apressure tube 31a leads to a diaphragm 32 suitably attached/to the fuel mixture tube of the' burner. 'A bell crank lever 33 is pivotally mounted at '34 adjacent thediaphragm and is related to .the diaphragm memberin a manner to be operated by the same. .The opposed) end 35,01. the

A translated to them through the lever 33 controlled by the diaphragm vand are adapted to be Withdrawn to a rearward or inoperative position where the sparking ends of the electrodes will rest upon parts of the vane members. A coil spring 40 exerts a pressure upon the bell crank, normally holding the electrodes in rearward position, but expansion of the diaphragm overcomes same and forces the electrodes forwardv t-o a sparking4 position. Again, with respect to the solenoid controlled valve 30, I find an openingF 41 at the base of said valve and a second valve member 42 controlled by the solenoid control valve, whereby the opening of said solenoid valve 3() will close the smaller valve and inversely the closing of said'solenoid valve will open the smaller valve 42. This action permits release of the pressure in the tube to yand collapse thereof after noid valve 30. 4

Having described the physical parts of my domestic fuel burner, I now come to the electrical .portions and they circuits included therein. l.

Y As is well known in the art, domestic fuel closing of the soledisposed vanes 26 burnersrefer mainly tooil burners adap'tl los as in all domestic fuel burners, a thermostat of well known design is located in any desirable portion of the dwelling to be heated,`and automatically controls the ope tionof the ,burnen The thermostat in th present instance is shown at T and is of the so-called h1gh volt-age type, meaning that it is adapted to receive the normal line voltage, usually volts. Tracing the electrical circuit in,7 Fig. 1, wh l shown, I find the 110^volt wire 100 from the 4 switch passing through the room thermostat T, and thence to theI safety switch S, which in the present instance is a trip switch controlled by a thermal member wound with a resistancelcoil. It might bey said at this time that the safety switch once thrown by the thermal member, must be manually reset bej fore the burner safety switch S comprises a contact strip the raising of the thermal strip 49" induced erein a diagram of same isl can resume activity. They 46- v faste-ned to a pivoted insulated plate 4T that 25 motor is running. The switch 103 is located by the heat caused by the resistance coil 50.

A i Obviously, the cooling of the thermal member and movement to its lowered position is necessary before 'the switch canfbe manually reset.

'F rom the safety switch, the'high voltage wire 100`leads to the electric motor and from same to a point where it divides, one side going to a short circuit switch 104 and the other side through the resistance coil on the safety switch, and thence to a switch 102 made only when the burner is in operation. The line through the resistance coil also leads to a switch member 103 which closes the circuit in said line when the burner, or yrather motor, is idle. y o

Before completing the description of the electrical circuit, the detail description of the switch mechanism controlling the various operations will be given. An insulated panel 7 5 contains a movable plate 76 thereon, which operates the switch 102 which closes the circuit only when the motor is running. A short circuit switch is shown at 104 on the sam-e panel, and closes the circuit only when the on the lower side of the plate and closes an electrical circuit only when the burner or motor is idle. The insulated plate 7G, or rather the movement thereoffis controlled by the action of the above described diaphragm 28 through the levers 29a, 7 8" and 79. As above described, the diaphragm, or rather the action thereof, is controlled by the operation of 113er. on the return electrical circuit wire 115,`

- the burner and more directly from the pressure raised in the liquid fuelair pressure pump. A connection which will be referred to as 111, leads from the contact on the right tion 113 in the stack thermostat leads from both sides of the mercury\bulb B, to a point i said wire being on the-other side of the high voltage circuit and leading tothe main or service switch 105. cuitA leads from the plural terminal member X, through the wire 116 to a formal 110 volt spark coil 117,` the circuit being completed through the wire 118 to another plural ter- 'minal member-Y, and the circuit continuing vthrough wire 111 to the stack thermostat and thence through the common wire 113 to the l other side of the 110 volt circuit. This is a bulb B. Wires 110 and 120 lead from the spark coil to the electrodes in the spark igmtion mechanism.

Another electrical cir-,

Still another circuit leads from the plural terminal member X, through the wire 122 to the coil 31, operating the solenoid which is actually the valve 30 in the pressure line between the liquid air compressor and the diaphragm 28, operating the lever 29a, which controls movement of the electrodes of the spark. This structure hasbeen described in detail above. The circuit is completed through the wire 124, which leads to the plural terminal Y, thence through the wire 111 to the stack thermostat and is finally completed through commonl wire 113 and the return wire 115 of the 110 volt circuit.

This is a temporary circuit for operating thespark withdrawal mechanism, and is controlled in exactly the same manner as the spark ignition member, namely by movement of the stack thermostat, induced by combustion conditions.

Although the actual wiring, included in the electrical circuits, has been described and numbered, nevertheless, a clearer understanding of said circuits will be thought gained by describing said circuits in connection with the operation of the automatically controlled burner.

As said before, the present burner is automatically controlled by a high voltage thermostat T located in a desired place in the dwelling to be heated. 'I will assume that:

the burner is idle; that the temperature of the dwelling has lowered to a point where the house thermostat T has been actuated, and the 110 volt or line circuit closed therethrough. This movement of the house thermostat to a closed, or rather on position, permits the 110 volt current to pass to the ,motor through the wire 100, which first goes to the safety switch S then through wire 125 to the plural terminal member B, thence through wire 126 to themotor, whereupon the motor isl immediately energized.

Tracing the 110 volt circuit, immediately upon the energizing of the motor, I find that said current passes from the motor through the wire 127 t-o the terminal Z passing through the wire 128 to the heat coil 50, thence through the wire 128 to a terminal 129, thence through the contact plate on the switch 103, which is closed for a short time immediately after the initial energizing of the motor, said current passing thereafter y through the wire 111 of the lright hand or cold side C of thestack thermostat. This current returns thro-ughr the common wire 113 to a point 113e where it connects with the other side, namely the wire of the 110 v volt circuit.

mercury contact bulb is controlled by ther- I sensitive to combustion conditions, and with relation to the present description of operation, I have called the right side of the 5 mercury bulb the cold side, in view of the fact that this bulb will have the circuit cornpleted through the wires 111 and 113, when the combustion chamber is at low temperature, this being namely while the burner is idle, and for a temporary period after the commencement of operation of the burner.,

Continuing the operation of the burner, as well as the description of the electrical circuits, I find that the main electrical circuit was completed immediately upon the throwing of the room thermostat. However, simultaneously with the completion of the above described circuit, the followingelectrical circuits were energized.

Starting at the plural terminal member X, I find the spark ignition circuitl which passes through the wire 116 to the spark coil and returning from the spark coil throughl the wire 118 to the plural terminal Y, thence through the wire 111 to the cold side of the mercury bulb in the stack thermostat, thence returning through the common Wire 113, in the stack thermostat, through said wire, and finally connecting with the return wire 115 in the 11() volt circuit. In other words, upon the initial energizing of the 110 volt circuit, the spark coil is simultaneously energized through the wires 119 and 120 and sparking at the contact points of the electrodes results, the same providing the means for igniting the projected fuel mixture, which is discharging during the operation of the burner.

At this time it is thought best to bring out the temporary action of the sparking mechanism, when it can be plainly seen that upon a rise in temperature in the combustion chamber, the stack thermostat will be moved with a similar action ofy the mercury bulb, whereupon the circuit will be opened between the wires 111 and 113, and de-energizing of the sparking circuit will immediately take place. It might be added, however, that prior to the de-energizing of the spark coil, other electrical actions take place, the same being as follows: Again, and'simultaneously with the initial energizing of the 110 volt circuit,and starting at the plural terminal X, I find the wire 122 carrying the electrical circuit therethrough to the coil 31 controlling the operation of the solenoid valve 30, said current returning from the coil'thr'ough the line` 124 to the plural terminal member Y, l thence through the wire 111 to the cold side of the stack thermostat, or rather, mercury bulb, then passing through the common wire 113, to the return wire 115 of the 110 volt circuit. Again, I ind'merely a temporary circuit At this time, relative to the mechanism for projecting and withdrawing the electrodes of the spark ignition mechanism, it might be said that upon the energizing of the coil 31 and thereby opening the circuit in the bulb t between the Wires 111 and 113.

surrounding the solenoid Valve 30, said valve is raised, and pressure from the air pressure pump is permitted to pass through the tube 31a, to the diaphragm 32, whereupon the bell crank lever 33 is moved to project the electrodes to a point within the cone of the projected fuel mixture.

From the above description, I find that I sparking is taking place across the Contact points yof these electrodes at this time and hence ignition of the projected fuel mixture takes place in this manner. This sparking takes place continuously with the solenoid valve action, inasmuch as both are controlled by the movement of the stack thermostat and hence both projection of the electrodes inte the zone of ignition, as well as sparking of the electrodes will continue until the temperature in the combustion chamber has risen to a point where the stack thermostat will be operated to open the electric circuit therethrough, hence cle-energizing the spark coil, releasing the coil surrounding the solenoid valve and prohibiting the passage of air under pressure to iniate the diaphragm. Collapse of the diaphragm, assisted by the opening of the small valve 42 and the tension of the spring 40, a ainst the bell crank, results in the imme iate withdrawal of the electrodes to a point where the contact portions thereof abut the angularly disposed vanes surrounding the nozzle. -This withdrawal of the electrodes against the vanes, both due to the collapse of the diaphragm and the action of the spring, automatically cleanses said electrodes -of any carbon or other deposits thereon. r

Continuing the description of the operation of the burner in connection with the electrical circuits therefor, it will be necessary to go back to a time just after the room thermostat has operated and the commencement of burner activity. I have described the immediate electrical circuit that was completed.

Now,l continuing the operation of the burner, Ijind that very shortly a pressure is created within the air pressure chamber, that said pressure is transmitted to the diaphragm 28, said diaphragm, through the levers?, 78 and 7 9, likewise transmitting ,movement to the insulated movable plate 7 5 in the panel 76. From the disclosure, it may be seen that this movable switch plate has its contact end moved downwardly, whereupon the movable ICI lili

contact arm of the switch 103 is moved away from stationary contact 10351.l Simultaneously with the movement of the movable contact on the switch 102` is the movement of the short circuiting switch 104, which makes contact with the stationary contact yportion 10aa thereof.

It might be said at thisA time that because of the fact that the con-tact is made between the movable Contact member 102 and the stationary contact102a, prior to the release of the movable contact member 103 from point 103a, noarcing of the ,contacts is possible, due to the changing circuits. After the release of the movable Contact member 103, the circuit passes through the .contact made previously by the movement of the movable contact 102 with the stationary contact102a, thence through the wire 115, which is the return wire of the 110 volt circuit. This operation of the' above described movable switch member 102 completes a shorter electrical circuit.for the electric motor and short-circuits out the portion of the same circuit which previously went through the stack thermostat. This operation, or rather slight changing, of circuits, is for the purpose of getting ready for the movement of the mer'cury bulb in the stack thermostat induced by the rising temperature in the combustion chamber, after ignition.

Again, the contact made, due to the movement of the short circuiting'switch 104, completes a circuit not yet made through the hot side of the stack thermostat, namely, through wires 113 and 112. This contact is made at this time and said circuit closed for the reason that it is getting readyfor` the move- ,ment of the mercury bulb to-the hot position and preparing to cut` out the current from going through the resistance or heat coil after the stack thermostat has operated.

Now, when the temperature in the-'combustion chamber is such, that the stack thermostat actually moves, and hence .tilts the mercury contact bulb, the electrical circuits to the solenoid valve and the spark ignition mechanism are opened, and at the same time the circuit through the short circuiting switch 104 is completed, ,thereby permitting the current which formerly went through the resistance coil 50 now to take a .short cut and to go through the wire 112, to the mercury bulb, then out the common, wire 113, and finally to the return 11,0.volt wire 115.

The burner is now', operating in a normal manner, and the dwelling is being-heated. When the temperature ofthe dwelling' has reached a point where the room thermostat is operated to shut the burner off, then cessa-- tion of the burner is occasioned by the opening of the 110 volt circuit, due to the tilting of the mercury contact bulb in the room thermostat. Upon the cessation of operationA of the burner, there follows naturally a lowering of the temperature in the combustion chamber, with the consequent movement of the stack thermostat to a cold position, namely, to the full line position shown in Fig. 1. now find the burner and electrical circuits `in exactly the same position in which I started my description of the operation.

It will be obvious from the above that upon either failure of initial ignitionor failure of combustion `conditions thereafter during burner activity, that the bulb in the stack thermostat will either be in or move to the cold position, whereupon after a determined time, the resistance coil 50 will heat up the thermal member 49, which will rise, release the latch on the safety switch,` hence opening the switch and stopping burner activity until manually reset. v

What I claim is:

1. The combination with an oil burner, of electrically operated means for discharging an atomized fuel mixture into a zone of ignition, ignition mechanism comprising sparking members energized simultaneously with the commencement of operation of the burner, pressure operated means for projecting said sparking members into the zone of the discharging fuel mixture, and pressure release mechanism operating after the occurrence of ignition for withdrawing said sparking members.

2. The combination with an oil burner, of electrically operated means `for discharging an atomized fuel mixture into a zone of ignition, ignition mechanism comprising a sparking member, pressure operated means controlled by the operation of the burner for projecting said sparking member into the zone of the discharging fuel mixture, and release mechanism permitting withdrawal of said sparking member thereafter comprising a pressure relief valve and a spring tension withdrawal member.

3. The combination with an oil burner, of electrically operated means for discharging an atomized fuel mixture into a zone of ignition, ignition mechanism comprising a sparking member, a pressure diaphragm member controlled by the operation of the burner adapted to project the sparking member into the zone of the discharging fuel mixture, and an electrically controlled valve member adapted to release the pressure and permit withdrawal of the sparking member after a sufficient period for ignition.

4.. The combination with an oil burner, of electrically operated means for discharging an atomized fuel mixture into a zone of ignition,` spark ignition mechanism energized simultaneously with the commencement of operation of the burner and pressure operated means for projecting the sparking member into the zone of the discharging fuel mixture, said pressure operated mechanism comprising an electrically controlled valve member energized simultaneously with the commencement of operation of the burner, said valve member operating after the occurrence of ignition to relieve the pressure and permit withdrawal of the sparking member.

5. In combination with an oil burner, of electrically powerdriven means for discharging a fuel mixture intova zone ofignition, a combustion chamber, spark ignition mechav10 nism and means comprising pressure operated mechanism automatically controlled by the operation of the burner for advancing and withdrawing said spark ignition mechanism from the zone of ignition. 6. In combination with an oil burner, of

electrically power driven means for discharging a fuel mixture into a zone lof ignition, a combustion chamber, spark ignition mechanism and means automaticallycontrolled by the operation of the burner for advancing and withdraw-ingsaid spark'ignition mech-- anism from the zone of ignition, said means including a pressure diaphragm controlling the movement 'of the spark ignition mecha- K25 nism, and mechanism for Withdrawing'said ignition mechanism, saidmechanism operc p afling upon a 'collapse of the pressure diap rag 7 In combination with an oil burner, of electrically power driven means for` discharging a fuel mixture into a zone of ignition, a combustion chamber, spark ignition mechanism, and means automatically controlled by the operation of the burner for advancing and ,withdrawing said spark ignition mechanism from the zone of igrition,.said means including a pressure diaphragm connected with the spark ignition mechanism, said diaphragm being controlled by the operation of the electrically power driven means.

In testimony whereof, I have hereunto set my hand at Peoria, Illinois,this 8th day of April, A. D. 1925.

LOYD I. ALDRICI-I. 

